Clinical variables impacting on the estimation of utilities in chronic obstructive pulmonary disease.

Author contributions MM participated in the design of the study and, as lead coordinating investigator, contributed to the analysis and review of the results. AH, together with the GlaxoSmithKline team, developed the idea of the study, and was involved in the design, monitoring of centers, and review of the results. JLLC, MV, and PGS participated as investigators and clinical experts in the development of the protocol and analysis of data. CC and CF were involved in the design of the study and the literature review, and carried out data collection, monitoring of centers, and analysis of the results. All authors contributed to the writing and review of the manuscript and have read and accepted the final version.